Final answer:
Polysaccharides, triacylglycerols, and proteins are all macromolecules, with each belonging to one of the major classes of biological molecules: carbohydrates, lipids, and proteins, respectively.
Step-by-step explanation:
Polysaccharides, triacylglycerols, and proteins are all similar in that they are types of macromolecules. Each of these is a major class of biological molecules essential for life, built from smaller organic molecules known as monomers.
Polysaccharides such as cellulose and starch are carbohydrates consisting of long chains of monosaccharides. Triacylglycerols (or triglycerides) are a type of lipid, specifically fats and oils, which are made of glycerol linked to three fatty acids. Proteins are made of amino acids and serve various functions in the cell, such as catalyzing biochemical reactions, signaling, and providing structure.